In our conditions, PAH stimulation led to decreased transcription of RORA and RORC genes, in agreement with the inhibitory effect observed on IL-17A, and to increased AhR target gene CYP1A1 expression concomitantly to IL-22 enhancement suggesting that PAH differentially regulate these cytokines at the transcriptional level in humans. This evidence concerns the gene CYP1A1 and pulmonary arterial hypertension.